Alpha-fetoprotein (AFP)
What is this test for?
AFP testing serves several functions depending on the clinical context. Outside of pregnancy, it primarily acts as a tumor marker to detect or monitor certain cancers. During pregnancy, it is part of combined prenatal screening to assess the risk of chromosomal abnormalities or neural tube defects in the fetus.
When is it recommended?
Your doctor may order this test in the following situations:
- Screening and surveillance of hepatocellular carcinoma in patients with cirrhosis or chronic hepatitis
- Therapeutic monitoring of known liver cancer to assess treatment response
- Suspicion of testicular or ovarian germ cell tumor (teratoma, yolk sac tumor)
- Second-trimester prenatal screening as part of a maternal serum marker screening
- Surveillance after treatment of an AFP-secreting tumor to detect recurrence
Results Interpretation
Reference values vary by laboratory, age, and clinical context. Interpretation should always be performed by a physician, taking into account the entire clinical picture.
| Context | Indicative rate | Possible meaning |
|---|---|---|
| Non-pregnant adult | Less than 10 ng/mL | Normal rate, absence of detectable tumor secretion |
| Moderate elevation | 10 – 200 ng/mL | Active hepatitis, cirrhosis, benign or malignant tumor to be confirmed |
| Significant elevation | 200 ng/mL | Strong suspicion of hepatocellular carcinoma or germ cell tumor |
| Pregnancy (2nd trimester) | Variable by week | Low levels: risk of Down syndrome; high levels: risk of spina bifida or twins |
What are the limitations of this test?
AFP is not a perfect marker. Several situations can distort its interpretation:
- A normal rate does not formally exclude liver cancer, as some tumors are non-secretory.
- A moderate elevation can be observed in benign liver diseases such as cirrhosis or active viral hepatitis
- In the prenatal context, the result must be interpreted with other markers and the fetal ultrasound.
- Maternal smoking may slightly alter the values during pregnancy
How do you prepare?
This test requires no special preparation. A simple blood sample is sufficient and can be taken at any time of day. Inform your doctor of any ongoing medication, known pregnancy, or liver condition to ensure optimal interpretation of the results.
Where to get this test done in Quebec?
This laboratory test is available at Clinique Omicron service points in Quebec. A medical prescription is required. Our healthcare professionals can assist you from the prescription to the interpretation of your results.
The content of this page is provided for informational purposes only and is not intended to replace the advice of a qualified healthcare professional. Consult a physician for any symptoms, questions or decisions you may have regarding your health.
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